 However, modern research says ″Although it was thought that folic acid might exacerbate vitamin B12 deficiency and its symptoms, it is probably not the case″.And that if this were the case then ″mechanisms by which folic acid exacerbates vitamin B12 deficiency remain unclear″

Administration of nitrous oxide anesthesia can precipitate subacute combined degeneration in people with subclinical vitamin B12 deficiency, while chronic nitrous oxide exposure can cause it even in persons with normal B12 levels.Posterior column dysfunction decreases vibratory sensation and proprioception (joint sense).